JP2012119129A - Luminous tube and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminous tube which simplifies production process, reduces color variations, and improves life properties, lamp efficiency, and reliability.SOLUTION: A first light emitting tube 10A includes a light emitting part 12 emitting light therein and a first ceramic tube 16A having a first narrow tube 14a and a second narrow tube 14b which are respectively and integrally formed on both sides of the light emitting part 12. In the first light emitting tube 10A, a first electrode 18a is inserted into the first narrow tube 14a of the first ceramic tube 16A to seal the first narrow tube 14a and a second electrode 18b is inserted into the second narrow tube 14b to seal the second narrow tube 14b, where the first electrode 18a is sealed in the first narrow tube 14a through thermal insertion.

Description

  The present invention relates to a light-emitting tube including a high-intensity discharge lamp such as a high-pressure sodium lamp or a metal halide lamp, and a method for manufacturing the same. A ceramic tube having a first thin tube and a second thin tube, wherein the first electrode is inserted and sealed in the first thin tube of the ceramic tube, and the second electrode is inserted and sealed in the second thin tube The present invention relates to an arc tube and a method for manufacturing the same.

  A ceramic metal halide lamp ionizes a metal halide with a pair of electrodes inserted into a ceramic tube for a high-intensity discharge lamp, thereby obtaining discharge light emission.

  This type of ceramic tube has a pair of tubules that are formed so as to be positioned so that the axis faces the light emitting portion. Each thin tube is provided with an electrode insertion hole, and an electrode is inserted through these electrode insertion holes. Various types of ceramic tubes are disclosed, such as those produced by assembling a plurality of members, those produced integrally as a single member, and those produced by joining two members.

  Then, for example, after inserting an electrode into one electrode insertion hole of two thin tubes provided in a ceramic tube and sealing it with frit glass or the like, a luminescent substance is put into the light emitting container through the remaining electrode insertion hole. After that, the electrode is inserted into the other electrode insertion hole and sealed with frit glass or the like to assemble the arc tube (see, for example, Patent Documents 1 to 4).

JP 2005-302624 A JP 2010-177092 A JP 2009-163983 A JP 2008-262728 A

  However, conventionally, when assembling into the arc tube, it is necessary to frit-sea the electrodes on both sides, and there is a problem that the number of assembling steps increases. After the ceramic tube is manufactured, the two electrodes are inserted into the corresponding thin tubes and sealed, and therefore it is necessary to make the inner diameter of each thin tube larger than the maximum diameter of the electrodes (the diameter of the tip). In addition, the electrode is positioned by placing a stopper in the form of a rod or ring on the electrode and contacting the stopper with the end of each ceramic tube (the end of each thin tube). The amount by which the tip of the electrode protrudes from the inner surface of the light emitting portion varies, and the variation in the distance from the inner surface of the light emitting portion increases, resulting in lamp color variations and a reduction in life. Further, since each electrode is positioned at both ends of the ceramic tube, if there is a variation in the total length of the ceramic tube, the distance between the two electrodes varies, resulting in a decrease in lamp efficiency and color variation. In addition, since there is a clearance between the narrow tube and the electrode lead, it is easy to shift during sealing, and the electrode position with respect to the central axis of the arc tube is not constant, causing color variations.

  As described above, since the diameter of the tip portion of the electrode cannot be made larger than the inner diameter of the thin tube, the electrode temperature tends to be high, resulting in a decrease in life. On the other hand, if the inner diameter of the thin tube is increased, the diameter of the electrode tip can be increased, but in this case, the gap between the electrode and the inner diameter of the thin tube is increased. As a result, the luminescent material tends to accumulate in the gap, and corrosion of the portion sealing the electrode tends to occur. Further, the amount of the luminescent material is not stable, and the position of the electrode with respect to the central axis of the arc tube is not constant, which causes color variation. In order to reduce the gap, if the diameter other than the tip of the electrode is increased in accordance with the inner diameter of the thin tube, the thermal stress due to the difference in thermal expansion coefficient between the electrode and the thin tube increases, and cracks occur in the thin tube. It becomes easy to do. Further, there is a problem that the lamp efficiency is lowered because the heat capacity of the electrode is increased.

  The present invention has been made in consideration of such problems, and can simplify the manufacturing process, and can reduce color variation, improve life characteristics, improve lamp efficiency, and improve reliability. An object of the present invention is to provide an arc tube and a method for manufacturing the same.

[1] A light emitting tube according to a first aspect of the present invention includes a ceramic tube having a light emitting portion that emits light therein, and first and second thin tubes integrally formed on both sides of the light emitting portion. In the arc tube in which the first electrode is inserted and sealed in the first thin tube of the ceramic tube, and the second electrode is inserted and sealed in the second thin tube, the first electrode is baked into the first thin tube. It is characterized by being sealed with a pin.

[2] In the first aspect of the present invention, the diameter of the portion of the first electrode that is shrink-fitted into the first capillary is 0.18 mm or more and 0.5 mm or less.

[3] In the first aspect of the present invention, the diameter of the tip of the first electrode is not less than 0.22 mm and not more than 2.0 mm, and is not less than 1.2 times and not more than 4 times the inner diameter of the first capillary. It is characterized by.

[4] In the first aspect of the present invention, the arc tube is turned on by a DC power source, the first electrode is a cathode electrode, the second electrode is an anode electrode, and the first capillary of the first electrode The diameter of the portion sealed in the second electrode is 0.2 to 0.9 times the diameter of the portion of the second electrode sealed in the second capillary.

[5] In the first aspect of the present invention, the ceramic tube has a first member integrally provided with a first small cylindrical portion that later becomes a first thin tube, and a second small cylindrical portion that later becomes a second thin tube. The second member provided on the first electrode and the first electrode are assembled and fired.

[6] In the first aspect of the present invention, the first electrode has a positioning portion that determines a tip position of the first electrode in the light emitting portion by contacting an end portion of the first capillary tube. And

[7] In the first aspect of the present invention, the first electrode has a positioning portion that determines a tip position of the first electrode in the light emitting portion by contacting an inner surface of the first member on the light emitting portion side. It is characterized by having.

[8] In the first aspect of the present invention, the first member includes a cylindrical part having a hollow part, one of which is an opening, and the first part provided integrally with a part of the cylindrical part facing the opening. And the second member has a plug portion that closes the opening of the cylindrical portion, and the second small cylindrical portion that is integrally provided at a central portion of the plug portion. It is characterized by.

[9] In the first aspect of the present invention, the second member includes a cylindrical portion having a hollow portion, one of which is an opening, and the first portion provided integrally with a portion of the cylindrical portion facing the opening. The first member has a plug portion that closes the opening of the cylindrical portion, and the first small cylindrical portion that is integrally provided at a central portion of the plug portion. It is characterized by.

[10] In the first aspect of the present invention, the first member has a first bending portion having a hollow portion, one of which is a first opening, and a portion of the first bending portion that faces the first opening. The first small cylindrical portion provided integrally therewith, and the second member includes a second bending portion having a hollow portion, one of which is a second opening, and among the second bending portions, The ceramic tube has the second small cylindrical portion provided integrally with a portion facing the second opening, and the ceramic tube includes the first opening and the second opening. And are joined so as to face each other.

[11] A method of manufacturing an arc tube according to a second aspect of the present invention includes a ceramic having a light emitting part that emits light therein, and first and second thin tubes integrally formed on both sides of the light emitting part. In a manufacturing method of an arc tube comprising a tube, wherein a first electrode is inserted and sealed in the first thin tube of the ceramic tube, and a second electrode is inserted and sealed in the second thin tube, A first member producing step of producing a first member which is pre-fired and has a first small cylindrical portion which will later become the first thin tube and a first through hole formed in the first small cylindrical portion in the axial direction; The second ceramic molded body is pre-fired to produce a second member having a second small cylindrical portion that will later become the second thin tube and a second through hole formed in the second small cylindrical portion in the axial direction. The second member manufacturing step, the first member, the second member and the An assembly process for assembling one electrode to produce an assembly; and firing the assembly to produce a ceramic tube having the light emitting portion, the first capillary tube and the second capillary tube; and A ceramic tube manufacturing step of sealing the first thin tube by shrink fitting, a step of introducing a luminescent substance through the second thin tube into the light emitting portion of the ceramic tube, and the second electrode being inserted into the second thin tube And an electrode sealing step for sealing.

[12] In the second aspect of the present invention, in the first member manufacturing step, the first member is manufactured by temporarily firing the first ceramic molded body at a first temperature, and the second member manufacturing step includes: The second ceramic molded body is pre-fired at a second temperature higher than the first temperature to produce the second member, and the ceramic tube manufacturing step includes a step of raising the assembly to a temperature higher than the second temperature. The ceramic tube is manufactured by firing at 3 temperatures.

[13] In the second aspect of the present invention, the first electrode has a positioning portion for determining a tip position of the first electrode at a rear end portion, the tip portion having a diameter smaller than the diameter of the first through hole. The assembling step assembles the second member, the first member, and the first electrode in this order so that the first member and the second member face each other, and the first electrode is assembled to the first electrode. The first through hole of the member is inserted until the positioning portion contacts a rear end of the first small cylindrical portion.

[14] In the second aspect of the present invention, in the first member manufacturing step, the first ceramic molded body is temporarily fired at a first temperature to manufacture the first member, and the second member manufacturing step includes: The second ceramic molded body is pre-fired at a second temperature lower than the first temperature to produce the second member, and the ceramic tube manufacturing step includes a step of raising the assembly to a temperature higher than the first temperature. The ceramic tube is manufactured by firing at 3 temperatures.

[15] In the second aspect of the present invention, the first electrode has a positioning portion for determining a tip position of the first electrode at a tip portion, the tip portion having a diameter larger than the diameter of the first through hole, In the assembling step, the first member, the first electrode, and the second member are assembled in this order so that the first member and the second member face each other, and the first electrode is connected to the first penetration. It has the process of inserting in the hole until the said positioning part contacts the end surface facing the said 2nd member.

  As described above, in the arc tube and the manufacturing method thereof according to the present invention, since one electrode is shrink-fitted, the assembly process of the arc tube can be simplified. Since the electrode can be positioned using the inner surface of the arc tube, the amount of the electrode protruding to the light emitting portion is constant, and the distance between the tip and the inner surface of the arc tube is constant. Further, since the thin tube and the electrode lead are in close contact with each other, there is no displacement of the electrode position with respect to the central axis of the arc tube, and it is possible to reduce color variation and improve lamp efficiency. Since the diameter of the tip of the electrode can be increased, the life characteristics are improved. On the other hand, since the shrink fit portion of the electrode can be made thin, cracks due to thermal stress can be prevented.

  As described above, according to the arc tube and the method for manufacturing the same according to the present invention, the manufacturing process can be simplified, and it is possible to reduce color variation, improve life characteristics, improve lamp efficiency, and improve reliability. it can.

It is sectional drawing which shows the structure of the arc tube (1st arc tube) which concerns on 1st Embodiment. FIG. 2A is a process diagram showing a state in which the first ceramic pre-fired body, the first ceramic pre-fired body, and the first electrode are assembled in this order to produce the first assembly, and FIG. 2B shows the first assembly. It is process drawing which shows the state which carried out this baking and was set as the 1st ceramic tube. It is a flowchart which shows the 1st manufacturing method for producing the 1st arc tube. 4A is a cross-sectional view showing a first ceramic molded body (or a second ceramic molded body), and FIG. 4B is a cross-sectional view showing a second ceramic molded body (or a first ceramic molded body). It is sectional drawing which shows the structure of the arc tube (2nd arc tube) which concerns on 2nd Embodiment. FIG. 6A is a process diagram illustrating a state in which the first assembly is manufactured in the order of the first ceramic pre-fired body, the first electrode, and the second ceramic pre-fired body, and FIG. 6B illustrates the second assembly. It is process drawing which shows the state which carried out this baking and was set as the 2nd ceramic tube. It is a flowchart which shows the 2nd manufacturing method for producing the 2nd arc tube. It is sectional drawing which abbreviate | omits and shows a structure of the arc_tube | light_emitting_tube (3rd arc_tube) which concerns on 3rd Embodiment. FIG. 9A is a cross-sectional view showing a first ceramic calcined body and a second ceramic calcined body, which are constituent members of an arc tube (fourth arc tube) according to the fourth embodiment, and FIG. It is sectional drawing which shows the structure of a pipe | tube. FIG. 10A is a cross-sectional view showing a first ceramic pre-fired body and a second ceramic pre-fired body, which are constituent members of an arc tube (fifth arc tube) according to the fifth embodiment, and FIG. It is sectional drawing which shows the structure of a pipe | tube.

  Embodiments of the arc tube and the manufacturing method thereof according to the present invention will be described below with reference to FIGS. In the present specification, “˜” indicating a numerical range is used as a meaning including numerical values described before and after the numerical value as a lower limit value and an upper limit value.

  The arc tube includes a high-pressure discharge lamp, and the high-pressure discharge lamp can be applied to various illumination devices such as road lighting, store lighting, automobile headlamps, and liquid crystal projectors. The arc tube includes an arc tube for a metal halide lamp and an arc tube for a high-pressure sodium lamp.

  First, as shown in FIG. 1, the arc tube according to the first embodiment (hereinafter referred to as the first arc tube 10A) includes a cylindrical light-emitting unit 12 that emits light inside, and the light-emitting unit 12. The first ceramic tube 16A having a cylindrical first thin tube 14a and a second thin tube 14b that are integrally formed on both sides of the first thin tube 14b. A first electrode 18a is inserted and sealed in the first thin tube 14a of the first ceramic tube 16A, and a second electrode 18b is inserted and sealed in the second thin tube 14b. In particular, in the first arc tube 10A, the first electrode 18a is sealed to the first thin tube 14a by shrink fitting. The second electrode 18b is sealed to the second thin tube 14b by a sealing material 20 such as glass frit.

  As shown in FIGS. 2A and 2B, the first ceramic tube 16A includes a first ceramic temporary fired body 24a obtained by temporarily firing the first ceramic molded body 22a and a second ceramic temporary fired product obtained by temporarily firing the second ceramic molded body 22b. It is configured by joining the fired body 24b and firing it.

  As shown in FIG. 2A, the first ceramic calcined body 24a includes a large cylindrical portion 30 having a hollow portion 28, one of which is an opening 26, and a portion (bottom portion) of the large cylindrical portion 30 that faces the opening 26. 32) and a first small through hole 36a penetrating from the end of the first small cylindrical portion 34a to the inner surface of the large cylindrical portion 30. And have. The second ceramic pre-fired body 24b has a disk shape that closes the opening 26 of the large cylindrical portion 30 of the first ceramic pre-fired body 24a and has a flat end face, A second small cylindrical portion 34b (a portion that will later become the second thin tube 14b) provided integrally with the central portion; a second through hole 36b penetrating from the end of the second small cylindrical portion 34b to the end surface of the plug portion 38; Have The inner surface of the bottom 32 in the large cylindrical portion 30 of the first ceramic temporary fired body 24 a on the hollow portion 28 side is a flat surface corresponding to the end surface of the plug portion 38.

  For example, as shown in FIG. 1, the first electrode 18a includes a first electrode shaft 40a, a first coil 42a wound around the tip of the first electrode shaft 40a, and a rear end of the first electrode shaft 40a. And a first lead 44a connected thereto. The first lead 44a is in the form of a rod or ring for positioning that determines the tip position of the first electrode 18a in the light emitting unit 12 by contacting the end of the first thin tube 14a (first small cylindrical portion 34a). The first stopper 46a is fixed. The maximum diameter of the first coil 42a is substantially the diameter of the tip of the first electrode 18a, and the tip of the first electrode shaft 40a protruding from the tip of the first coil 42a is the tip of the first electrode 18a. .

  In particular, the diameter of the tip of the first electrode 18a is slightly smaller than the inner diameter of the first through hole 36a in the first ceramic temporary fired body 24a, and is 1.2 times or more and 4 times the inner diameter of the first capillary 14a. It is as follows. In this case, it is preferable that it is 0.22 mm or more and 2.0 mm or less. Further, the diameter of the portion of the first electrode 18a that is shrink-fitted into the first capillary 14a, that is, the diameter of the first lead 44a is 0.18 mm or more and 0.5 mm or less, and the inner diameter of the first capillary 14a. The pressure is set to be slightly larger, and is adjusted so that a crimping force due to firing shrinkage acts on the boundary between the two. Further, the diameter of the first lead 44a is smaller than the diameter of the tip portion of the first electrode 18a. Note that the length or outer diameter of the first stopper 46a is larger than the inner diameter of the first through hole 36a and smaller than the outer diameter of the first capillary 14a.

  On the other hand, the second electrode 18b is connected to the second electrode shaft 40b, the second coil 42b wound around the tip of the second electrode shaft 40b, and the rear end of the second electrode shaft 40b, and has a diameter of And a second lead 44b that is larger than the diameter of the two-electrode shaft 40b. A ring-shaped second stopper 46b for positioning that determines the tip position of the second electrode 18b in the light emitting section 12 is fixed to the second lead 44b by contacting the end of the second capillary 14b. . The maximum diameter of the second coil 42b is substantially the diameter of the tip of the second electrode 18b, and the tip of the second electrode shaft 40b protruding from the second coil 42b is the tip of the second electrode 18b.

  The diameter of the tip of the second electrode 18b is smaller than the inner diameter of the second capillary 14b, and the diameter of the second electrode shaft 40b is smaller than the diameter of the second lead 44b. The outer diameter of the second stopper 46b is larger than the inner diameter of the second capillary 14b and smaller than the outer diameter of the second capillary 14b. That is, the inner diameter of the second thin tube 14b is larger than the inner diameter of the first thin tube 14a.

  The first arc tube 10A can be used in either an alternating current system or a direct current system, and in particular, when used in a direct current system, the temperature of the cathode electrode is lower than that of the anode electrode. The light emitting material easily enters the minute gaps of the light, and the invading light emitting material cannot be returned to the light emitting portion due to liquefaction and solidification, so that the light flux may be reduced. In order to avoid this, it is preferable to use the first electrode 18a having no gap between the ceramic and the electrode as the cathode electrode. Further, since a large temperature difference between the anode electrode and the cathode electrode causes color unevenness, the first electrode 18a is used as the cathode electrode, the second electrode 18b is used as the anode electrode, and the first lead 44a in order to balance the temperature. Is preferably 0.2 times or more and 0.9 times or less than the diameter of the second lead 44b.

  Here, a manufacturing method (first manufacturing method) for manufacturing the first arc tube 10A will be described with reference to FIG.

  In step S1 of FIG. 3, as shown in FIGS. 4A and 4B, a first ceramic molded body 22a and a second ceramic molded body 22b are produced. Specifically, first, a ceramic powder, a dispersion medium, a gelling agent, and the like are mixed to prepare a gel casting slurry (referred to as a forming slurry). Thereafter, the molding slurry is cast in a first casting mold for molding the first ceramic molded body 22a and in a second casting mold for molding the second ceramic molded body 22b, and then solidified. Thereafter, the first casting mold 22a and the second casting mold 22b are obtained by releasing the first casting mold and the second casting mold.

  Next, in step S2, the first ceramic molded body 22a is temporarily fired at a first temperature to produce a first ceramic temporary fired body 24a as shown in FIG. 2A. As the first temperature, a temperature at which the densification level of the first ceramic molded body 22a is low, for example, 700 ° C. to 1200 ° C. can be adopted. When the temperature is low, the strength of the first ceramic pre-fired body 24a is insufficient, and is easily damaged during assembly. Since the pre-baking is generally performed in the air, if the pre-baking temperature is high, it becomes difficult to densify by the subsequent baking. Therefore, the pre-baking temperature is preferably within the above range.

  Thereafter, in step S3, the second ceramic molded body 22b is temporarily fired at the second temperature to produce the second ceramic temporary fired body 24b. The second temperature is a temperature at which the level of densification of the second ceramic molded body 22b is higher than the level of densification of the first ceramic molded body 22a, for example, a temperature higher by 50 ° C to 300 ° C than the first temperature. Can do. If the difference between the first temperature and the second temperature is small, the dimensional difference between the two is small, which may cause scratches and nicks due to insufficient clearance during assembly. Also, if the temperature difference is large and the dimensional difference is large, the amount of shrinkage until the two are fixed increases, and the inclination between the first ceramic temporary fired body 24a and the second ceramic temporary fired body 24b tends to occur. The range of is preferable.

  Thereafter, in step S4, as shown in FIG. 2A, the first ceramic temporary fired body 24a, the second ceramic temporary fired body 24b, and the first electrode 18a are assembled to produce a first assembly 50A. At this time, the plug portion 38 of the second ceramic pre-fired body 24b is inserted so as to close the opening 26 of the first ceramic pre-fired body 24a, and the first through hole 36a of the first ceramic pre-fired body 24a is further inserted into the first through hole 36a. The first assembly 50A is obtained by inserting the electrode 18a.

  Specifically, a jig 54 having a through hole 52 to the extent that the second small cylindrical portion 34 b of the second ceramic temporary fired body 24 b is inserted is used, and the second small cylindrical portion 34 b is inserted into the through hole 52 of the jig 54. The plug portion 38 of the second ceramic temporary fired body 24b is placed on the upper surface 54a of the jig 54, and the second ceramic temporary fired body 24b is placed on the large cylindrical portion 30 of the first ceramic temporary fired body 24a from above. By placing the first ceramic temporary fired body 24a on the jig 54 so as to cover the plug portion 38, the plug of the second ceramic temporary fired body 24b is closed so as to close the opening 26 of the first ceramic temporary fired body 24a. Part 38 can be inserted. Thereafter, the first electrode 18a is inserted through the first through hole 36a from the rear end of the first small cylindrical portion 34a of the first ceramic temporary fired body 24a. At this time, the first electrode 18a is inserted through the first through hole 36a until the first stopper 46a contacts the rear end of the first small cylindrical portion 34a. Thereby, the first assembly 50A is completed.

  Thereafter, in step S5, with the first assembly 50A placed on the jig 54, the first assembly 50A is subjected to main firing at a third temperature to obtain a sintered body. When the plug portion 38 of the second ceramic temporary fired body 24b is fired alone, the outer diameter after firing is adjusted to be 1 to 9% larger than the inner diameter after firing of the opening 26 of the first ceramic temporary fired body 24a. Therefore, a crimping force acts on the interface between the two due to firing shrinkage. In addition, since the first lead 44a of the first electrode 18a is adjusted to be slightly larger than the inner diameter of the first capillary 14a, a crimping force acts on the boundary surface between them due to firing shrinkage. 2B, the light emitting unit 12, the first capillary 14a, and the second capillary 14b are integrated, and the first electrode 18a is sealed to the first capillary 14a by shrink fitting. One ceramic tube 16A is obtained. The third temperature may be a temperature aimed at densification and translucency of the first assembly 50A, for example, 1700 ° C. to 1900 ° C. By this main firing, the inner diameter of the first through-hole 36a of the first ceramic temporary fired body 24a is reduced by, for example, about 20% to 40%, and the first electrode 18a inserted through the first through-hole 36a becomes the first capillary 14a. It will be shrink-fitted and sealed. As a result, the diameter of the tip of the first electrode 18a is larger than the inner diameter of the first capillary 14a.

  In addition, the main firing causes the first assembly 50A to shrink as a whole, but mainly the first ceramic provisional fired body 24a shrinks greatly, along the axis of the first small cylindrical portion 34a (the first thin tube 14a). The length is also shortened. As a result, the tip portion of the first electrode 18a is separated from the inner surface 12a (ceramic wall surface) near the first capillary 14a of the light emitting unit 12, and the distance from the inner surface 12a to the tip position of the first electrode 18a is the first electrode. It becomes larger than the length in the axial direction of the tip end portion (first coil 42a) of 18a. Since this distance varies depending on the amount of firing shrinkage, that is, the relative density of the molded body, when a large number of the first ceramic tubes 16A are produced, the distance is made constant by keeping the relative density of the molded body constant. It can be made substantially constant between the tubes 16A.

  Thereafter, in step S6, a luminescent material is introduced through the second thin tube 14b into the light emitting part 12 of the first ceramic tube 16A. That is, mercury and a metal halide additive are introduced into the light emitting section 12 in addition to an inert start gas such as argon. It is not always necessary to introduce mercury.

  In step S7, the second electrode 18b is inserted and sealed in the second capillary 14b. Specifically, as shown in FIG. 1, the second electrode 18b is inserted into the second capillary 14b together with the sealing material 20 to seal the second electrode 18b. At this time, the second electrode 18b is inserted until the second stopper 46b contacts the rear end of the second capillary 14b. Thereafter, the sealing material 20 is attached so as to cover the second stopper 46b, and the second electrode 18b is hermetically sealed. At this stage, the first arc tube 10A is completed.

  In the first arc tube 10A and the first manufacturing method thereof described above, the first electrode 18a is shrink-fitted on the first narrow tube 14a of the first ceramic tube 16A by utilizing the main firing of the first assembly 50A. Since sealing is performed, it is not necessary to seal the first electrode 18a to the first thin tube 14a using the sealing material 20, and the assembly process of the first arc tube 10A can be simplified. When producing the plurality of first ceramic tubes 16A, the tip position of the first electrode 18a can be made substantially constant between the plurality of first ceramic tubes 16A by making the relative density of the molded body constant. . Further, since the first capillary 14a and the first lead 44a are in close contact, the position of the first electrode 18a with respect to the central axis of the first arc tube 10A is constant. This leads to a reduction in color variation and an improvement in lamp efficiency. Since the diameter of the tip of the first electrode 18a (the diameter of the first coil 42a) can be made larger than the inner diameter of the first capillary 14a, the cooling effect by the first coil 42a can be maintained for a long time, Life characteristics can be improved. In particular, in a direct current type arc tube, the lifetime of the arc tube itself is determined by the lifetime of the cathode electrode, but the lifetime of the first arc tube 10A can be extended by using the first electrode 18a as a cathode electrode. . In addition, the inner diameter of the first thin tube 14a can be reduced without being governed by the diameter of the tip of the first electrode 18a. Thereby, since the diameter of the 1st electrode shaft 40a and the 1st lead 44a which contact the 1st thin tube 14a among the 1st electrodes 18a can be made thin, the thermal expansion of the 1st thin tube 14a and the 1st electrode 18a is carried out. An increase in thermal stress due to the rate difference can be prevented. This leads to the prevention of cracks. In addition, since the diameters of the first electrode shaft 40a and the first lead 44a can be reduced, the heat capacity of the first electrode 18a is reduced, and a decrease in lamp efficiency due to the first electrode 18a can be suppressed.

  As described above, according to the first arc tube 10A and the first manufacturing method thereof, the manufacturing process can be simplified, and the color variation can be reduced, the life characteristics can be improved, the lamp efficiency can be improved, and the reliability can be improved. Can do.

  Next, an arc tube according to a second embodiment (hereinafter referred to as a second arc tube 10B) will be described with reference to FIGS.

  As shown in FIG. 5, in the second arc tube 10B, the light emitting unit 12, the first narrow tube 14a, and the second thin tube 14b are integrated in substantially the same manner as the first arc tube 10A described above, and the first narrow tube 14a is integrated with the first arc tube 14a. One electrode 18a has a second ceramic tube 16B sealed by shrink fitting, but differs in the following points. The second electrode 18b is sealed to the second thin tube 14b by a sealing material 20 such as glass frit.

  That is, as shown in FIGS. 6A and 6B, the configurations of the first ceramic temporary fired body 24a and the second ceramic temporary fired body 24b are opposite to those of the first arc tube 10A. Specifically, the second ceramic pre-fired body 24b is integrated with a large cylindrical portion 30 having a hollow portion 28, one of which is an opening 26, and a bottom portion 32 of the large cylindrical portion 30 facing the opening 26. The second small cylindrical portion 34 b provided and a second through hole 36 b penetrating from the end of the second small cylindrical portion 34 b to the inner surface of the large cylindrical portion 30 are provided. The first ceramic pre-fired body 24a is a disc-shaped plug portion 38 that closes the opening 26 of the large cylindrical portion 30 of the second ceramic pre-fired body 24b, and a first portion integrally provided at the center of the plug portion 38. A small cylindrical portion 34a and a first through hole 36a penetrating from an end portion of the first small cylindrical portion 34a to an end surface of the plug portion 38 are provided.

  The first electrode 18a includes a first electrode shaft 40a, a first coil 42a wound around the tip of the first electrode shaft 40a, and a first lead fixed to a part of the side surface of the first electrode shaft 40a. 44a. Then, the first lead 44a is inserted into the first through hole 36a of the first ceramic temporary fired body 24a toward the rear end of the first small cylindrical portion 34a, whereby the rear end of the first electrode shaft 40a is plugged. It will contact | abut to the end surface 38a of 38. That is, by making the length of the first electrode shaft 40a in the axial direction constant among the plurality of second arc tubes 10B, the rear end of the first electrode shaft 40a positions the tip position of the first electrode 18a. It functions as a positioning part.

  Here, a manufacturing method (second manufacturing method) for manufacturing the second arc tube 10B will be described with reference to FIG.

  First, in step S101 of FIG. 7, as shown in FIGS. 4A and 4B, a first ceramic molded body 22a and a second ceramic molded body 22b are produced. In FIGS. 4A and 4B, the reference numerals of the first ceramic molded body 22a and the second ceramic molded body 22b should be referred to the reference numerals shown in parentheses. Specifically, after mixing a ceramic powder, a dispersion medium, a gelling agent and the like to prepare a molding slurry, the molding slurry is cast into a first casting mold and a second casting mold and solidified. Thereafter, the first casting mold 22a and the second casting mold 22b are obtained by releasing the first casting mold and the second casting mold.

  Next, in step S102, the first ceramic molded body 22a is temporarily fired at a second temperature (eg, 1200 ° C.) to produce a first ceramic temporary fired body 24a. In step S103, the second ceramic molded body 22b is The second ceramic temporary fired body 24b is produced by temporary firing at one temperature (for example, 1000 ° C.).

  Thereafter, in step S104, as shown in FIG. 6A, the first ceramic temporary fired body 24a, the second ceramic temporary fired body 24b, and the first electrode 18a are assembled to produce the second assembly 50B. At this time, the first electrode 18a is inserted into the first through hole 36a of the first ceramic temporary fired body 24a, and the first ceramic temporary fired body 24a is inserted so as to close the opening 26 of the second ceramic temporary fired body 24b. Thus, the second assembly 50B is obtained.

  Specifically, in this case as well, a jig 54 having a through hole 52 to the extent that the first small cylindrical portion 34 a of the first ceramic temporary fired body 24 a is inserted is used, and the first small hole is inserted into the through hole 52 of the jig 54. The plug portion 38 of the first ceramic pre-fired body 24a is placed on the upper surface 54a of the jig 54 through the cylindrical portion 34a. Thereafter, the first electrode 18a is inserted into the first through hole 36a of the first ceramic temporary fired body 24a toward the rear end of the first small cylindrical portion 34a. At this time, the first electrode 18a is inserted through the first through hole 36a until the rear end of the first electrode shaft 40a contacts the end face of the first ceramic temporary fired body 24a (end face 38a of the plug portion 38). At this stage, the positioning of the first electrode 18a is completed. Then, by placing the second ceramic temporary fired body 24b on the jig 54 so as to cover the plug portion 38 with the large cylindrical portion 30 of the second ceramic temporary fired body 24b from above, the second ceramic temporary fired body is placed. The first ceramic temporary fired body 24a can be inserted so as to close the opening 26 of 24b. At this stage, the second assembly 50B is completed.

  Thereafter, in step S105, in a state where the second assembly 50B is placed on the jig 54, the sintered body is fired at a third temperature for the purpose of densification and translucency of the second assembly 50B. obtain. That is, the light emitting unit 12, the first capillary tube 14a, and the second capillary tube 14b are integrated to obtain the second ceramic tube 16B in which the first electrode 18a is sealed by shrink fitting in the first capillary tube 14a. At this time, the second assembly 50B shrinks as a whole, but the second ceramic pre-fired body 24b shrinks greatly compared to the first ceramic pre-fired body 24a. Moreover, since the first stopper 46a as shown in FIG. 2B is not fixed to the first lead 44a, the rear end of the first electrode shaft 40a is connected to the end surface 38a of the plug portion 38 of the first ceramic pre-fired body 24a. The contact state is maintained, and the rear end of the first electrode shaft 40a is in contact with the inner surface 12a (ceramic wall surface) of the light emitting unit 12 near the first thin tube 14a. That is, the positioning state of the tip position of the first electrode 18a by the rear end of the first electrode shaft 40a is maintained. Even if there is a variation in the relative density of the molded body among the plurality of second ceramic tubes 16B, unlike the case of producing the first ceramic tube 16A, the distance from the tip of the first electrode 18a to the positioning portion. Is short, the amount of shrinkage is small, and it is difficult to be affected. This leads to stabilization of the tip position of the first electrode 18a. Further, since the first lead 44a and the first thin tube 14a are in close contact with each other, the position of the first electrode 18a with respect to the central axis of the second arc tube 10B is stabilized.

  Thereafter, in step S106, a luminescent material is introduced into the light emitting portion 12 of the second ceramic tube 16B through the second thin tube 14b. In step S <b> 107, the second electrode 18 b is inserted into the second thin tube 14 b and sealed with the sealing material 20. At this stage, the second arc tube 10B is completed.

  In the above-described second arc tube 10B and the second manufacturing method thereof, as in the case of the first arc tube 10A, the manufacturing process can be simplified, color variation can be reduced, life characteristics can be improved, and lamp efficiency can be improved. Reliability can be improved. In particular, in the second arc tube 10B, the first electrode 18a can be positioned using the inner surface of the first ceramic temporary fired body 24a (the end surface 38a of the plug portion 38). The distance from the inner surface of the second arc tube 10B becomes constant, so that color variation can be reduced and lamp efficiency can be improved.

  Next, an arc tube according to a third embodiment (hereinafter referred to as a third arc tube 10C) will be described with reference to FIG.

  As shown in FIG. 8, the third arc tube 10 </ b> C includes a third ceramic tube 16 </ b> C that is substantially the same as the second arc tube 10 </ b> B described above, but the configuration of the first electrode 18 a is different in the following points.

  That is, the first electrode 18a has a first electrode shaft 40a whose axial length is greater than the axial length of the first capillary, and the first electrode shaft 40a is close to the first coil 42a. A rod-shaped or ring-shaped first stopper 46a that is fixed to the portion to be made and whose length or outer diameter is larger than the inner diameter of the first through hole 36a (see FIG. 6A) of the first ceramic pre-fired body 24a. .

  Then, in the manufacturing process of the third arc tube 10C, the first electrode shaft 40a is inserted into the first through hole 36a of the first ceramic temporary fired body 24a, for example, as shown in FIG. 6A, and the rear end of the first small cylindrical portion 34a. The rear end of the first stopper 46a comes into contact with the end surface of the first ceramic pre-fired body 24a (end surface 38a of the plug portion 38). In other words, by fixing the fixed position of the first stopper 46a among the plurality of third arc tubes 10C, the rear end of the first stopper 46a functions as a positioning unit for positioning the front end position of the first electrode 18a. Will do.

  The third arc tube 10C can also be manufactured by the second manufacturing method for manufacturing the second arc tube 10B similar to FIG. The third arc tube 10C also has the same effect as the second arc tube 10B described above. In particular, since the axis of the first electrode 18a and the axis of the second electrode 18b can be substantially matched, the light emission efficiency can be further improved. In the above description, the first electrode shaft 40a is shrink-fitted into the first thin tube, but the first lead 44a is preferably connected coaxially to the rear of the first electrode shaft 40a, and a portion of the first lead 44a. It is preferable to perform the shrink-fitting configuration because the diameters of the first electrode shaft 40a and the shrink-fitted portion can be freely selected.

  Next, an arc tube according to a fourth embodiment (hereinafter referred to as a fourth arc tube 10D) will be described with reference to FIG.

  As shown in FIGS. 9A and 9B, the fourth arc tube 10D is formed by integrating the light emitting unit 12, the first capillary tube 14a, and the second capillary tube 14b in substantially the same manner as the first arc tube 10A described above. 14a has the fourth ceramic tube 16D in which the first electrode 18a is sealed by shrink fitting, but differs in the following points. The second electrode 18b is sealed to the second thin tube 14b by a sealing material 20 such as glass frit.

  That is, as shown in FIG. 9A, the first ceramic calcined body 24a includes a first curved portion 56a having a first hollow portion 28a, one of which is a first opening 26a, and the first curved portion 56a. A first small cylindrical portion 34a provided integrally with a portion facing the first opening 26a, and a first through hole 36a penetrating from the end of the first small cylindrical portion 34a to the inner surface of the first curved portion 56a. Have.

  The second ceramic temporary fired body 24b includes a second curved portion 56b having a second hollow portion 28b, one of which is a second opening 26b, and a portion of the second curved portion 56b that faces the second opening 26b. It has the 2nd small cylindrical part 34b provided integrally, and the 2nd through-hole 36b penetrated from the edge part of the 2nd small cylindrical part 34b to the inner surface of the 2nd curved part 56b.

  The first electrode 18a includes a first electrode shaft 40a whose axial length is larger than the axial length of the first through hole 36a, and a first electrode 18a wound around the tip of the first electrode shaft 40a. 1 coil 42a. A ring-shaped first stopper 46a for positioning that determines the tip position of the first electrode 18a in the light emitting unit 12 by being in contact with the end of the first small cylindrical portion 34a is integrated with the first electrode shaft 40a. Is formed.

  The fourth arc tube 10D can also be manufactured by the first manufacturing method for manufacturing the first arc tube 10A similar to FIG. In this case, the end face on the first opening 26a side of the first ceramic pre-fired body 24a and the end face on the second opening 26b side of the second ceramic pre-fired body 24b are joined using joining slurry. The fourth arc tube 10D also has the same effect as the first arc tube 10A described above.

  Next, an arc tube according to a fifth embodiment (hereinafter referred to as a fifth arc tube 10E) will be described with reference to FIGS. 10A and 10B.

  As shown in FIGS. 10A and 10B, in the fifth arc tube 10E, the light emitting unit 12, the first capillary tube 14a, and the second capillary tube 14b are integrated in substantially the same manner as the second arc tube described above, and the first capillary tube 14a is integrated. The first electrode 18a has a fifth ceramic tube 16E sealed by shrink fitting, but differs in the following points. The second electrode 18b is sealed to the second thin tube 14b by a sealing material 20 such as glass frit.

  That is, as shown in FIG. 10A, the bottom portion 32 of the large cylindrical portion 30 of the second ceramic temporary fired body 24b has a curved shape that is concave toward the first ceramic temporary fired body 24a to be joined. The inner surface on the hollow portion 28 side is also a curved surface. The end surface 38a of the plug portion 38 in the first ceramic pre-fired body 24a corresponds to the curved surface of the second ceramic pre-fired body 24b, and is a curved surface that is recessed toward the second ceramic pre-fired body 24b to be joined. It is said that.

  The fifth arc tube 10E can also be manufactured by the second manufacturing method for manufacturing the second arc tube 10B similar to FIG. The fifth arc tube 10E also has the same effect as the second arc tube 10B described above.

  Here, preferable aspects, such as a material used for the manufacturing method which concerns on this Embodiment, are demonstrated. In addition, when saying the 1st manufacturing method and the 2nd manufacturing method mentioned above collectively, it only describes as "manufacturing method", and when mentioning the 1st ceramic molded object 22a and the 2nd ceramic molded object 22b mentioned above collectively, This is simply referred to as a ceramic molded body.

(Ceramic molded body)
In the manufacturing method described above, a ceramic molded body is prepared. Various methods are conventionally known for producing a ceramic molded body, and can be easily obtained using such methods. As a method for producing a ceramic molded body, for example, a molding slurry containing an inorganic powder and an organic compound is cast into a casting mold and solidified by a chemical reaction between organic compounds, for example, a chemical reaction between a dispersion medium and a gelling agent or gelling agent. After that, it can be prepared by a gel casting method for releasing the mold. Such a forming slurry contains a dispersion medium and a gelling agent in addition to the raw material powder, and may contain a dispersing agent and a catalyst for adjusting viscosity and solidification reaction. Hereinafter, these various components will be described.

(Raw material powder)
Examples of the ceramic powder contained in the ceramic molded body include alumina, aluminum nitride, zirconia, YAG, and a mixture of two or more thereof. Examples of the sintering aid for improving the sinterability and characteristics include magnesium oxide, and ZrO ₂ , Y ₂ O ₃ , La ₂ O ₃ and Sc ₂ O ₃ are preferable.

(Dispersion medium)
As the dispersion medium, it is preferable to use a reactive dispersion medium. For example, it is preferable to use an organic dispersion medium having a reactive functional group. The organic dispersion medium having a reactive functional group can be chemically bonded to a gelling agent described later, that is, a liquid substance capable of solidifying the molding slurry, and can form a highly fluid molding slurry that can be easily cast. It is preferable to satisfy the two conditions of being either a liquid substance. In order to chemically bond with the gelling agent and solidify the molding slurry, a reactive functional group, that is, a functional group capable of forming a chemical bond with the gelling agent such as a hydroxyl group, a carboxyl group, or an amino group is included in the molecule. It is preferable to have.

  On the other hand, in order to form a molding slurry having high fluidity that is easy to cast, it is preferable to use an organic dispersion medium having a viscosity as low as possible, and in particular, a substance having a viscosity at 20 ° C. of 20 cps or less is used. It is preferable.

  In addition, it is effective to use polyhydric alcohol and polybasic acid for strength reinforcement as long as they do not greatly thicken the molding slurry.

(Gelling agent)
The gelling agent reacts with the reactive functional group contained in the dispersion medium to cause a solidification reaction, and is described, for example, on page 21 to page 22 line 9 of WO 2002/085590. Those exemplified below can also be used.

  It is desirable that the reactive functional group of the gelling agent should be strong enough to not be deformed by a load at the time of bonding after causing a solidification reaction in order to perform bonding while maintaining the groove shape. From this point of view, an isocyanate group (—N═C═O) and / or an isothiocyanate group (−) having particularly high solvent resistance after the solidification reaction and additionally high reactivity with the reactive dispersant. It is preferred to select a gelling agent having N = C = S).

  The molding slurry for producing the ceramic molded body can be exemplified by the contents described in Japanese Patent Application Laid-Open No. 2008-44344 and International Publication No. 2002/085590. For example, it is prepared as follows. Can do. First, the raw material powder is dispersed in a dispersion medium to form a molding slurry, and then a gelling agent is added, or the raw material powder and the gelling agent are simultaneously added to the dispersion medium and dispersed to form a molding slurry. it can.

(Production of sintered body (ceramic tube))
Next, two or more prepared ceramic molded bodies, or a ceramic calcined body obtained by calcining the ceramic molded body in the atmosphere, is assembled using the above-described jig or the like together with the first electrode. Alternatively, a joined body is produced. Thereafter, the assembly or bonded body is fired to obtain a sintered body. Prior to the sintering step, the assembly or joined body can be degreased or calcined.

(electrode)
Various known materials can be used for the electrode material that is shrink-fitted or sealed on the ceramic tube. For example, the electrode shaft and coil are W (tungsten), and the lead is W, Mo (molybdenum), Nb (niobium), Ir (iridium), Re (rhenium), Ru (ruthenium), etc. from the viewpoint of melting point and thermal expansion. It is mentioned as preferable.

(Joining slurry)
When joining ceramic pre-fired bodies to obtain a joined body, a joining slurry is prepared. The joining slurry is preferably a non-self-curing slurry that does not solidify by a chemical reaction. For the bonding slurry, various binders such as polyvinyl acetal resin and ethyl cellulose can be used in addition to the raw material powder and non-reactive dispersion medium that can be used for the molding slurry already described. Further, a dispersant such as DOP (bis (2-ethylhexyl phthalate)) or an organic solvent such as acetone or isopropanol for adjusting the viscosity at the time of mixing can also be used.

  The joining slurry can be obtained by mixing raw material powder, a solvent, and a binder using a normal ceramic paste using a tri-roll mill, a pot mill, or the like, or a slurry production method. A dispersant and an organic solvent can be appropriately mixed. Specifically, butyl carbitol, butyl carbitol acetate, terpineol, or the like can be used.

[First embodiment]
The occurrence of cracks in the arc tube produced by the manufacturing methods according to Examples 1 and 2 and Comparative Example 1 and the amount of leakage of the light emitting part were measured. Furthermore, the variation in the tip position of the first electrode (the variation in the distance from the ceramic wall surface to the tip position of the first electrode) was confirmed.

Example 1
Based on the first manufacturing method shown in FIG. 3, ten arc tubes (first arc tube 10A) shown in FIG. 1 were produced. In this case, the inner diameter of the first thin tube 14a of the first ceramic tube 16A was 0.5 mm, and the inner diameter of the second thin tube 12b was 0.8 mm.

  First, a molding slurry for producing the first ceramic molded body 22a and the second ceramic molded body 22b (see FIGS. 4A and 4B) was prepared as follows. That is, 100 parts by weight of alumina powder as a raw material powder and 0.025 part by weight of magnesia, 30 parts by weight of a polybasic acid ester as a dispersion medium, 4 parts by weight of MDI resin as a gelling agent, 2 parts by weight of a dispersant, 0. Two parts by weight were mixed to form a molding slurry.

  This molding slurry was poured into a first casting mold and a second casting mold made of aluminum alloy at room temperature, left at room temperature for 1 hour, solidified, and then released. Furthermore, it was left to stand at room temperature and then at a temperature of 90 ° C. for 2 hours to obtain 10 first ceramic molded bodies 22a and 10 second ceramic molded bodies 22b, respectively.

  Thereafter, the first ceramic molded body 22a manufactured as described above is temporarily fired in the atmosphere at a temperature of 1000 ° C. to produce a first ceramic temporary fired body 24a, and the second ceramic molded body 22b is heated to a temperature of 1200 in the atmosphere. The second ceramic calcined body 24b was calcined at 0 ° C. 2A, the second ceramic temporary fired body 24b, the first ceramic temporary fired body 24a, and the first electrode 18a are sequentially assembled to produce the first assembly 50A, and then hydrogen: nitrogen = It was fired at a temperature of 1800 ° C. in a 3: 1 atmosphere to make it densified and translucent. The thing of the range of 0.505-0.52mm was used so that the outer diameter of the 1st electrode 18a may become 1.01-1.04 times the internal diameter of the 1st thin tube 14a. Further, the diameter of the first coil 42a at the electrode tip was 0.7 mm. As a result, from the first assembly 50A, the outer diameter of the light emitting section 12 is 11 mm, the lengths of the first capillary 14a and the second capillary 14b in the axial direction are 17 mm, and the first electrode 18a is baked on the first capillary 14a. A sintered body (first ceramic tube 16A) sealed with a fit was obtained. Thereafter, the second electrode 18b was sealed with a glass frit in the second thin tube 14b to produce ten arc tubes (first arc tube 10A) according to Example 1. The outer diameter of the second electrode 18b was 0.72 mm so as not to get caught in the second capillary 14b.

The ten arc tubes obtained were not cracked or deformed. When the thermal shock resistance was evaluated by an underwater quenching method, each arc tube was not cracked even at 150 ° C. and was at the same level as a ceramic tube having the same shape without the first electrode 18a and the second electrode 18b. Further, after evaluating the thermal shock resistance of these arc tubes, the leak amount of the light emitting part was measured with a He leak measuring device, and all were 1 × 10 ⁻⁸ atm · cc / sec or less. Further, when the variation in the distance from the ceramic wall surface 12a of the ten arc tube prototypes to the tip position of the first electrode 18a was evaluated, the difference between the maximum distance and the minimum distance was 0.10 mm. Moreover, when the deviation | shift amount from the center axis | shaft of the arc tube of the 1st electrode 18a was measured, all were 0.01 mm or less.

(Example 2)
Ten sintered bodies (second ceramic tube 16B) shown in FIG. 5 were produced based on the second manufacturing method shown in FIG. Also in this case, the inner diameter of the first capillary 14a was made smaller than the inner diameter of the second capillary 14b.

  First, ten first ceramic molded bodies 22a and ten second ceramic molded bodies 22b (see FIGS. 4A and 4B) were produced in the same manner as in Example 1 described above.

  Thereafter, the first ceramic molded body 22a produced as described above is temporarily fired in the atmosphere at a temperature of 1200 ° C. to produce the first ceramic temporary fired body 24a, and the second ceramic molded body 22b is heated to a temperature of 1000 in the atmosphere. The second ceramic calcined body 24b was calcined at 0 ° C. 6A, the first ceramic temporary fired body 24a, the first electrode 18a, and the second ceramic temporary fired body 24b are sequentially assembled to produce the second assembly 50B, and then hydrogen: nitrogen = It was fired at a temperature of 1800 ° C. in a 3: 1 atmosphere to make it densified and translucent. As a result, from the second assembly 50B, the outer diameter of the light emitting section 12 is 11 mm, the lengths of the first capillary 14a and the second capillary 14b in the axial direction are 17 mm, and the first electrode 18a is baked on the first capillary 14a. A sintered body (second ceramic tube 16B) sealed with a fit was obtained. Thereafter, the second electrode 18b was sealed with a glass frit in the second thin tube 14b to produce ten arc tubes (second arc tube 10B) according to Example 2.

The ten arc tubes obtained were not cracked or deformed. When the thermal shock resistance was evaluated by an underwater quenching method, each arc tube was not cracked even at 150 ° C. and was at the same level as a ceramic tube having the same shape without the first electrode 18a and the second electrode 18b. Further, after evaluating the thermal shock resistance of these arc tubes, the leak amount of the light emitting part was measured with a He leak measuring device, and all were 1 × 10 ⁻⁸ atm · cc / sec or less. Further, when the variation in the distance from the ceramic wall surface 12a of the ten arc tube prototypes to the tip position of the first electrode 18a was evaluated, the difference between the maximum and minimum distances was 0.05 mm. Moreover, when the deviation | shift amount from the design value was measured about the distance with the center axis | shaft of the arc tube of the 1st electrode 18a, all were 0.01 mm or less.

(Comparative Example 1)
Based on the first manufacturing method shown in FIG. 3, ten arc tubes similar to FIG. 1 were produced. In this case, the inner diameter of the first capillary 14a and the inner diameter of the second capillary 14b were set to 0.8 mm.

  First, ten first ceramic molded bodies 22a and ten second ceramic molded bodies 22b were produced in the same manner as in Example 1 described above.

  Thereafter, the first ceramic molded body 22a manufactured as described above is temporarily fired in the atmosphere at a temperature of 1000 ° C. to produce a first ceramic temporary fired body 24a, and the second ceramic molded body 22b is heated to a temperature of 1200 in the atmosphere. The second ceramic calcined body 24b was calcined at 0 ° C. Then, after assembling the first ceramic temporary fired body 24a and the second ceramic temporary fired body 24b in order using the jig 54 of FIG. 2A to produce an assembly, the temperature is increased in an atmosphere of hydrogen: nitrogen = 3: 1. Baking was performed at 1800 ° C. to make it dense and translucent. As a result, the outer diameter of the light emitting section 12 is 11 mm, the axial length of the first capillary 14 a and the second capillary 14 b is 17 mm, and the electrodes are inserted into the first capillary 14 a and the second capillary 14 b from the assembly. An unsintered sintered body (ceramic tube) was obtained. Thereafter, the first electrode 18a and the second electrode 18b were sealed with glass frit in the first capillary 14a and the second capillary 14b, respectively, and ten arc tubes according to Comparative Example 1 were manufactured.

  The ten arc tubes obtained were not cracked or deformed. However, when the thermal shock resistance was evaluated by an underwater quenching method, each arc tube was cracked at a temperature of 150 ° C. due to the frit sealing portion of the first thin tube 14a. Furthermore, after evaluating the thermal shock resistance of these arc tubes, the leak amount was measured with a He leak measuring machine, and leaks occurred in two arc tubes out of 10 sintered bodies. Further, when the variation in the distance from the ceramic wall surface 12a of the ten arc tubes manufactured as prototypes to the tip position of the electrode was evaluated, the difference between the maximum distance and the minimum distance was 0.10 mm. Moreover, when the deviation | shift amount from the center axis | shaft of the arc_tube | light_emitting_tube of the 1st electrode 18a was measured, they were 0.03 mm-0.04 mm.

[Second Embodiment]
In the arc tube manufactured by the first manufacturing method shown in FIG. 3, the crack generation state when the diameter of the first lead 44a (shrink fit portion) of the first electrode 18a is changed, the deformation of the tip of the first electrode Confirmed the occurrence of (falling).

(Example 3)
Based on the first manufacturing method shown in FIG. 3, except that the diameter of the first lead 44 a (shrink-fitted portion) of the first electrode 18 a is 0.18 mm, 10 arc tubes (first arc tube 10A) shown in FIG.

Example 4
Based on the first manufacturing method shown in FIG. 3, the ten leads shown in FIG. 1 are the same as in the first embodiment except that the diameter of the first lead 44a of the first electrode 18a is 0.50 mm. An arc tube (first arc tube 10A) was produced.

(Reference Example 1)
Based on the first manufacturing method shown in FIG. 3, the ten leads shown in FIG. 1 are the same as in the first embodiment except that the diameter of the first lead 44a of the first electrode 18a is 0.15 mm. An arc tube (first arc tube 10A) was produced.

(Reference Example 2)
Based on the first manufacturing method shown in FIG. 3, the ten leads shown in FIG. 1 are the same as in the first embodiment except that the diameter of the first lead 44a of the first electrode 18a is 0.60 mm. An arc tube (first arc tube 10A) was produced.

<Evaluation>
Evaluation was performed as follows.
(Number of cracks in the first tubule)
In each arc tube obtained, it was inspected whether or not a crack was generated in the first capillary tube. In Reference Examples 1, 2, and Examples 3 and 4, cracks occurred in 10 arc tubes each. I confirmed the number.

(Deformation of electrode tip)
In each arc tube obtained, whether the axis of the tip of the first electrode is tilted with respect to the axis of the first lead 44a (the portion that is shrink-fitted), that is, whether the tip of the electrode is deformed. Inspected, in Reference Examples 1 and 2, and Examples 3 and 4, the number of deformed electrode tips was confirmed among 10 arc tubes.

(Evaluation results)
The evaluation results are shown in Table 1.

  From the results shown in Table 1, it can be seen that the diameter of the shrink-fitted portion of the first electrode 18a is preferably in the range of 0.18 to 1.50 mm. The same result was obtained even when the arc tube was produced based on the second manufacturing method shown in FIG.

[Third embodiment]
With respect to the arc tube produced by the first manufacturing method shown in FIG. 3, the lamp effective time and the lamp efficiency were confirmed when the magnification of the diameter of the tip of the first electrode 18a with respect to the inner diameter of the first capillary 14a was changed.

(Example 5)
Based on the first manufacturing method shown in FIG. 3, except that the magnification of the diameter of the tip of the first electrode 18a with respect to the inner diameter of the first capillary 14a is 1.2, the same as in Example 1 described above, Ten arc tubes (first arc tube 10A) shown in FIG. 1 were produced.

(Example 6)
Based on the first manufacturing method shown in FIG. 3, the ten arc tubes (first arc tube 10A) shown in FIG. 1 are formed in the same manner as in Example 1 except that the magnification is set to 4. Produced.

(Reference Example 3)
Based on the first manufacturing method shown in FIG. 3, the ten arc tubes (first arc tube 10A) shown in FIG. 1 are used in the same manner as in Example 1 except that the magnification is 1.1. ) Was produced.

(Reference Example 4)
Based on the first manufacturing method shown in FIG. 3, the ten arc tubes (first arc tube 10A) shown in FIG. 1 are formed in the same manner as in Example 1 except that the magnification is 5. Produced.

<Evaluation>
Evaluation was performed as follows.
(Lamp effective time)
A continuous lighting test was performed on each arc tube obtained, and the time from the lighting start time to the time when the brightness decreased to 80% at the start of lighting (effective time functioning as a lamp) was measured.

  And the effective time of Example 5 was set to h (hour), and the ratio of Example 6 and the reference examples 3 and 4 was seen.

(Lamp efficiency)
The lamp efficiency is shown as a relative value with the lamp efficiency of Example 5 as 100.

(Evaluation results)
The evaluation results are shown in Table 2.

  From the results shown in Table 2, it can be seen that the range of 1.2 to 4 is preferable as the magnification of the diameter of the tip of the first electrode 18a with respect to the inner diameter of the first capillary 14a. The same result was obtained even when the arc tube was produced based on the second manufacturing method shown in FIG.

[Fourth embodiment]
Regarding the arc tube (type to be lit by a DC power supply) manufactured by the first manufacturing method shown in FIG. 3, of the second electrode 18b, the diameter of the portion sealed by the first thin tube 14a in the first electrode 18a The cathode side (first capillary side) when the magnification with respect to the diameter of the portion sealed by the second capillary 14b (hereinafter referred to as the magnification of the diameter of the first electrode 18a with respect to the diameter of the second electrode 18b) is changed. The occurrence of cracks and the lamp efficiency were confirmed.

(Example 7)
1 based on the first manufacturing method shown in FIG. 3, except that the magnification of the diameter of the first electrode 18a with respect to the diameter of the second electrode 18b is 0.9, as shown in FIG. Ten arc tubes (the first arc tube 10A) shown were produced.

(Example 8)
Based on the first manufacturing method shown in FIG. 3, the ten arc tubes (first arc tube 10A) shown in FIG. 1 are used in the same manner as in Example 1 except that the magnification is 0.2. ) Was produced.

(Reference Example 5)
Based on the first manufacturing method shown in FIG. 3, the ten arc tubes (first arc tube 10A) shown in FIG. 1 are used in the same manner as in Example 1 except that the magnification is 1.0. ) Was produced.

(Reference Example 6)
Based on the first manufacturing method shown in FIG. 3, the ten arc tubes (first arc tube 10A) shown in FIG. 1 are used in the same manner as in Example 1 except that the magnification is set to 0.1. ) Was produced.

<Evaluation>
Evaluation was performed as follows.
(Number of cathode side cracks)
In each arc tube obtained, the cathode side (first capillary tube side) is inspected for cracks, and in Reference Examples 5, 6, and Examples 7 and 8, each of 10 arc tubes, The number of cracks was confirmed.

(Lamp efficiency)
The lamp efficiency is shown as a relative value with the lamp efficiency of Example 7 as 100.

(Evaluation results)
The evaluation results are shown in Table 3.

  From the results shown in Table 3, it can be seen that the ratio of the diameter of the first electrode 18a to the diameter of the second electrode 18b is preferably in the range of 0.2 to 0.9. The same result was obtained even when the arc tube was produced based on the second manufacturing method shown in FIG.

  It should be noted that the arc tube and the manufacturing method thereof according to the present invention are not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

10A to 10E ... 1st arc tube-5th arc tube 12 ... Light emission part 14a ... 1st thin tube 14b ... 2nd thin tube 16A-16E ... 1st ceramic tube-5th ceramic tube 18a ... 1st electrode 18b ... 2nd electrode DESCRIPTION OF SYMBOLS 20 ... Sealing material 22a ... 1st ceramic molded object 22b ... 2nd ceramic molded object 24a ... 1st ceramic temporary baking body 24b ... 1st ceramic temporary baking body 34a ... 1st small cylindrical part 34b ... 2nd small cylindrical part 36a ... 1st through-hole 36b ... 2nd through-hole 38 ... Plug part 40a ... 1st electrode shaft 42a ... 1st coil 44a ... 1st lead 46a ... 1st stopper 46b ... 2nd stopper 50A ... 1st assembly 50B ... 1st assembly 2 assembly 56a ... 1st bending part 56b ... 2nd bending part

Claims (15)

A ceramic tube having a light emitting portion that emits light inside and a first thin tube and a second thin tube integrally formed on both sides of the light emitting portion, and a first electrode on the first thin tube of the ceramic tube. In the arc tube in which the second electrode is inserted and sealed in the second capillary,
An arc tube characterized in that the first electrode is sealed by shrink fitting in the first thin tube. The arc tube of claim 1, wherein
The arc tube according to claim 1, wherein a diameter of a portion of the first electrode that is shrink-fitted into the first capillary is 0.18 mm or more and 0.5 mm or less. The arc tube of claim 1, wherein
The diameter of the front-end | tip part of the said 1st electrode is 0.22 mm or more and 2.0 mm or less, and is 1.2 times or more and 4 times or less of the internal diameter of a said 1st thin tube, The arc tube characterized by the above-mentioned. The arc tube according to claim 1, wherein the arc tube is lit by a DC power source,
The first electrode is a cathode electrode, the second electrode is an anode electrode, and a diameter of a portion of the first electrode sealed by the first capillary is the second capillary of the second electrode. An arc tube having a diameter of 0.2 to 0.9 times the diameter of the sealed portion The arc tube of claim 1, wherein
The ceramic tube includes a first member integrally provided with a first small cylindrical portion to be a first thin tube later, a second member integrally provided with a second small cylindrical portion to be a second thin tube later, An arc tube characterized in that the first electrode is assembled and fired. The arc tube of claim 5, wherein
The arc tube according to claim 1, wherein the first electrode has a positioning portion that determines a tip position of the first electrode in the light emitting portion by contacting an end portion of the first thin tube. The arc tube of claim 5, wherein
The arc tube according to claim 1, wherein the first electrode has a positioning portion that determines a tip position of the first electrode in the light emitting portion by contacting an inner surface of the first member on the light emitting portion side. The arc tube of claim 5, wherein
The first member has a cylindrical portion having a hollow portion, one of which is an opening, and the first small cylindrical portion provided integrally with a portion of the cylindrical portion facing the opening,
The arc tube according to claim 1, wherein the second member includes a plug portion that closes the opening of the cylindrical portion, and the second small cylindrical portion that is integrally provided at a central portion of the plug portion. The arc tube of claim 5, wherein
The second member has a cylindrical portion having a hollow portion, one of which is an opening, and the second small cylindrical portion provided integrally with a portion of the cylindrical portion facing the opening,
The arc tube according to claim 1, wherein the first member includes a plug portion that closes the opening of the cylindrical portion, and the first small cylindrical portion that is integrally provided at a central portion of the plug portion. The arc tube of claim 5, wherein
The first member includes a first bending portion having a hollow portion, one of which is a first opening, and the first small portion provided integrally with a portion of the first bending portion facing the first opening. A cylindrical portion,
The second member includes a second bending portion having a hollow portion, one of which is a second opening, and the second small portion provided integrally with a portion of the second bending portion facing the second opening. A cylindrical portion,
The arc tube according to claim 1, wherein the ceramic tube is formed by joining the first member and the second member so that the first opening and the second opening face each other. A ceramic tube having a light emitting portion that emits light inside and a first thin tube and a second thin tube integrally formed on both sides of the light emitting portion, and a first electrode on the first thin tube of the ceramic tube. In the manufacturing method of the arc tube in which the second electrode is inserted and sealed in the second capillary,
The first ceramic molded body is pre-fired to produce a first member having a first small cylindrical portion that will later become the first thin tube and a first through hole formed in the first small cylindrical portion in the axial direction. A first member manufacturing step;
The second ceramic molded body is pre-fired to produce a second member having a second small cylindrical portion that will later become the second thin tube and a second through hole formed in the second small cylindrical portion in the axial direction. A second member manufacturing step;
An assembly step of assembling the first member, the second member, and the first electrode to produce an assembly;
The ceramic body is fired to produce a ceramic tube having the light emitting portion, the first capillary tube, and the second capillary tube, and the first electrode is sealed to the first capillary tube by shrink fitting. Production process;
Introducing a luminescent material through the second capillary into the light emitting part of the ceramic tube;
A method for manufacturing an arc tube, comprising: an electrode sealing step of inserting and sealing the second electrode into the second thin tube. In the manufacturing method of the arc tube according to claim 11,
In the first member manufacturing step, the first ceramic molded body is temporarily fired at a first temperature to prepare the first member,
In the second member manufacturing step, the second ceramic molded body is pre-fired at a second temperature higher than the first temperature to prepare the second member,
In the ceramic tube manufacturing step, the ceramic tube is manufactured by firing the assembly at a third temperature higher than the second temperature. The method of manufacturing an arc tube according to claim 12,
The first electrode has a positioning portion for determining a tip position of the first electrode at a rear end portion, the tip portion having a diameter smaller than the diameter of the first through hole,
The assembly process includes
Assembling the second member, the first member, and the first electrode in this order so that the first member and the second member face each other,
The method of manufacturing an arc tube, wherein the first electrode is inserted into the first through hole of the first member until the positioning portion contacts a rear end of the first small cylindrical portion. In the manufacturing method of the arc tube according to claim 11,
In the first member manufacturing step, the first ceramic molded body is temporarily fired at a first temperature to prepare the first member,
In the second member manufacturing step, the second ceramic molded body is temporarily fired at a second temperature lower than the first temperature to manufacture the second member,
In the ceramic tube manufacturing step, the ceramic tube is manufactured by firing the assembly at a third temperature higher than the first temperature. The method of manufacturing an arc tube according to claim 14,
The first electrode has a positioning portion for determining the tip position of the first electrode at the tip portion, the tip portion having a diameter larger than the diameter of the first through hole,
The assembly process includes
Assembling the first member, the first electrode, and the second member in order, with the first member and the second member facing each other,
A method of manufacturing an arc tube comprising the step of inserting the first electrode into the first through hole until the positioning portion contacts an end surface facing the second member.

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